1. Field of the Invention
The present invention relates to a flame resistant staple fiber blend. More particularly, the present invention relates to a flame resistant staple fiber blend useful for flame-resistant clothing, etc., for people who may be exposed to flame, for example, firemen, airmen, racing car drivers, and operators of electric power factories and chemical factories.
2. Description of the Related Arts
It is known that flame-retarded cotton, wool fibers and flame retardant polyvinyl alcohol fibers and rayon fibers are resistant to flame and are non-heat fusible, and thus are useful for making flame-resistant clothing.
Some of the above-mentioned fibers, however, are disadvantageous in that they do not have a satisfactory flame-resistance when used as flame-resistant clothing, or heat resistance after a prolonged exposure to a high temperature of 200.degree. C. or more.
It is also known that carbonized rayon fibers and polybenzimidazol fibers have an excellent heat and flame-resistance and are useful for heat and flameresistant clothing. These fibers, however, are disadvantageous in that the dyeability thereof is poor, and thus such fibers are not satisfactory when used for clothing. Also, they do not have a satisfactory touch and mechanical strength.
Accordingly, currently, poly(m-phenylene isophthalamide) fibers, which exhibit a satisfactory heat and flame resistance and mechanical strength and can be dyed any color, are widely used for flameresistant clothing. The m-aramide polymer fibers, however, are disadvantageous in that when exposed to flame, the m-aramide polymer fiber clothing is easily thermally shrunk, perforated, and broken.
To overcome the above-mentioned disadvantages of the m-aramide polymer fibers, Japanese Unexamined Patent Publication (Kokai) No. 49-110,921 discloses a flame-resistant fiber article comprising 20 to 90% by weight of wholly aromatic polyamide fibers and 10 to 80% by weight of flame-retardant fibers which are carbonized while maintaining the form of fibers thereof when exposed to flame.
The wholly aromatic polyamide fibers are the same as the m-aramide polymer fibers.
The heat and flame resistance of the frameresistant fiber article disclosed by the Japanese Kokai '921 is still not satisfactory in that, when exposed to flame, the fiber article cannot be maintained in the form of the article without perforation and breakage over a time necessary to be extricated from the flame. Namely, the conventional flame-resistant fiber article is not usable in a specific condition or atmosphere.